Mark Kerrigan, 45, remains in jail today, a day after openly sobbing in the courtroom as he pleaded not guilty to charges of assaulting an elderly person. Daniel Kerrigan died Sunday in his Massachusetts home after the two scuffled during an argument over a phone call.

"After the autopsy this case could be considered a homicide, which means the death was caused by a person," ABC News chief law and justice correspondent Chris Cuomo said today on "Good Morning America." "If authorities are able to ... connect what Mark did to his father, the choking, to the death, then he could get hit with a homicide charge."

Play

null

Mickey Sherman, a Connecticut criminal defense attorney who is not working on the case, said today that even if prosecutors go for a murder charge, the best they can hope for is a manslaughter conviction because there was seemingly no intent to kill.

"Of course it's his fault," Sherman said of Mark Kerrigan. "He set off this chain of events."

Though prosecutors often "over charge" defendants in these types of cases expecting a plea deal, Sherman said the family's high-profile name alone could lead to a murder charge for Kerrigan.

"If they do it, it'll be because of public pressure," he said.

Mark Kerrigan was held on $10,000 bail despite his lawyer's request to a judge to release him on a "personal promise" so he would be able to grieve with his family.

"It makes you so sad to think an argument potentially over a telephone could have led to this," ABC News sports contributor Christine Brennan told "Good Morning America" today.

But the tragedy could significantly worsen if police determine that Mark Kerrigan's alleged assault on his 70-year-old father led to his death, whether from his injuries or from a heart attack.

Both the timeline and the causation will be key elements in making that determination, Cuomo said.

"You're going to have to show that between the time that the choking was done and the death happened, the heart attack, as it's alleged right now … that that was the cause for it."

Making that case would be "not that simple," Cuomo said. "A charge is more likely than a conviction for that in this case."

Mark Kerrigan's lawyer made a point of noting that the brother of the famous Olympic figure skater suffered from post-traumatic stress disorder as a result of his time in the military. But Kerrigan also has a lengthy history with the law and has served time in prison.

There was no word on when the autopsy results were expected, and Kerrigan is due back in court at the end of February.

Nancy Kerrigan's Father 'a Great Guy'

Brennan, author of "Inside Edge: A Revealing Journey into the Secret World of Figure Skating," described the Kerrigan family as hard working and blue collar. Daniel Kerrigan, she said, was "a hockey dad stuck amongst the sequins."

"A real man, a real dad and a great guy," she said.

Daniel Kerrigan, a welder, worked three jobs at a time to support his daughter's career on the ice.

"What's money?" he asked in 1992. "I've been broke all my life. I'll be broke the rest of my life. It doesn't matter."

The murky circumstances of his death have stunned many.

Even Tonya Harding, Nancy Kerrigan's one-time chief rival who was banned from figure skating for her role in an attack on Kerrigan before the 1994 Olympics, released a statement after the attack.

"Tonya feels very sad for Nancy and her family and extends her deepest sympathy and condolences to them," the statement read. "Tonya's beloved dad, Al Harding, passed away this past April, so she understands the grief Nancy and her family are feeling at this difficult time."

Local and state police were called to the house in Stoneham, Mass., at 1:30 a.m., where they found Daniel Kerrigan, 70, "in need of medical attention." He was taken to Winchester Hospital where he was pronounced dead, according to a statement from Middlesex County District Attorney Gerry Leone.

"He [Mark Kerrigan] stated that he wanted to use the phone, and his father would not let him,'' according to a Stoneham police report filed in court. "He said that he struggled with his father and put his hands around his father's neck, and his father fell to the floor. He said that his father was faking it.''

According to the report, Mark Kerrigan appeared intoxicated -- smelling of alcohol and seen trying to conceal a bottle of whiskey -- and was belligerent as police officers tried to help his father. Police said in the report they found blood near where Kerrigan was found and pictures knocked off the walls.

"Officer Mahone grabbed his [Mark's] arm when Kerrigan became belligerent and combative. We were finally able to handcuff him. While handcuffed, I used pepper spray to help control the situation," reads the police report.

Nancy Kerrigan's Mother Says Husband Died From Heart Attack

Reached by phone, Brenda Kerrigan, Nancy's mother, told ABCNews.com that her husband died from a heart attack.

"I'll tell you something, it's a shock. It was a massive heart attack. That's how he died, that's it," said Brenda Kerrigan.

Nancy Kerrigan won a silver medal at the 1994 Winter Olympics in Lillehammer, Norway. She became the center of a media firestorm when, a month before the Games, she was attacked by Tonya Harding's ex-husband.

Kerrigan retired from active competition after the 1994 Olympics. She has appeared in occasional skating exhibitions, and had a small part in the 2007 Will Ferrell film "Blades of Glory."

In 1995, Kerrigan married her agent, Jerry Solomon. They live a few miles away from her parents' home in Lynnfield, Mass. Calls from ABCNews.com to Solomon requesting comment were not immediately returned.

Mark Kerrigan has a lengthy police record of petty crimes, including marijuana possession and a history of domestic troubles with his ex-wife and parents.

In a 2005 domestic-abuse incident with wife Tammy Kerrigan, police found Mark drunk and throwing things in the yard, according to a police report obtained by the New York Daily News.

As recently as Jan. 8, a lawyer for Mark Kerrigan filed documents in an ongoing appeal of charges of assault with a deadly weapon and malicious destruction of property dating from 2006.

According to civil documents found by the Boston Globe, Daniel and Brenda Kerrigan sued Mark for $105,000 for money they shelled out to take care of his dogs, pay the mortgage on his home in Wilmington, Mass., and pay the lawyer who represented him in the assault case.

At the time of the suit, Mark was serving time in a Middlesex County prison.

The judge dismissed the case, saying there was no evidence that his parents entered an "agreement or expectation of reimbursement from him," according to documents.